The invention relates to the field of DNA-guided particle assembly and, in particular, to three dimensional structuring of DNA-guided particle assemblies.
The ability to regulate the kinetic behavior of DNA-based nanosystems is required for emerging nanoparticle applications in sensing, nano-device assembling, and gene delivery. DNA based methodology takes advantage of the tunable and programmable hybridization between DNA-capped nanomaterials. This approach has allowed for the development of sensitive detection systems based on the optical and physical properties of assembled nanoparticles, as well as detection based on their novel melting/disassembly properties.
Currently, the self-assembly of metallic (gold, silver, platinum), semiconductive (CdSe, CdTe, CdSeZnS), and magnetic (Fe2O3, FePt) nanoparticles is separated into two classes, organic solvent based systems, and aqueous solution based systems. Each system has its advantages and disadvantages. In the organic solvent systems, nanoparticles are encapsulated with a dense shell of hydrophobic ligands (alkanethiol monolayers, polymers, multidentate ligands). The advantage of this class of nanoparticles is that the field is more mature, the particles are extremely stable, and a number of assembly routes for layer-by-layer assembly of nanoparticles on surfaces, or controlled aggregates in solution have been demonstrated. The disadvantage of this class is a lack of addressable chemistries at the nanoparticle surface, the harsh organic solvent environment (toluene, hexane, etc.), and the lack of tunable post-assembly structuring.
In contrast, while the use of aqueous based nanoparticle systems is not as mature, it may offer advantages over the organic solvent systems. First, it does not suffer from environmental concerns related to the solvent, and second, the systems allow for the functionalization of the nanoparticles with either biologically active or biologically mimicked surface encapsulation. For example, the ability of nature to self-assemble DNA, proteins, lipids, and extended hierarchies of multiple components is unrivaled by human synthetic capabilities.
Metamaterials are a class of ordered nanocomposites that exhibit exceptional properties not readily observed in nature. To benefit from their application in the fields of optics, magnetics, and medicine, three-dimensional structures created from individual nanoparticles are required. Current methods, including lithographic and traditional self-assembly approaches, are limited in their ability to fabricate three-dimensional structures with controllable order and particle-particle distance.
Precise positioning and ordered organization of nano-objects in three dimensions, a key to the creation of functional devices and new magnetic, plasmonic, and photonic metamaterials, is a challenging and actively developing frontier of nanoscience. Diverse self-assembled ordered phases have been observed for binary mixtures of uncapped nanoparticles as a result of the delicate interplay of geometrical factors, charges, and dipole and steric interactions. An alternative approach of using biomolecules to guide nanoparticle assembly is perceived to be advantageous due to the tunability of interparticle distances and assemblage structure. In addition, the addressability of bio-interactions may allow for rational creation of multi-component systems, while the rich energetic landscape of biomolecular conformations offers feasibility of dynamically reconfigurable systems. Some of these properties have been demonstrated with designed protein and DNA scaffolds, which have been employed to position nano-objects in one and two dimensions. The behavior of DNA functionalized micro- and nano-objects and their assembly in three dimensions has been the subject of extensive optical, structural and theoretical studies. However, long-range three-dimensional (3D) ordering via the addressable biological interactions has remained elusive.